 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
209.181.8.237
In Reply to: RE: This long thread just tells me what commercial SETs aren't.... posted by Tre' on September 03, 2017 at 07:22:00
Yes, it does, some of it. Some signal goes thru the resistor,
much of it through the capacitors.. The caps, of course
conduct mostly A.C. Any D.C. component through them is
due to capacitor leakage.The cathode resistor conducts both A.C.(signal) and D.C.,
and it generates artifacts concerning both. Not only does
the capacitor conduct signal, but it is also a filter in
that it shunts the resistor concerning the part of the
A.C. signal that is flowing thru the resistor.What you have here is two signal conducting devices--
the resistor and the caps-- the resistor conducts most
of the D.C., and plenty of A.C., and the caps conduct
nearly all A.C.It's a small composite SYSTEM.
Each component has a profound effect on the sound
qualities of the tube's plate and cathode signals.-Dennis-
Edits: 09/03/17 09/03/17Follow Ups:
"Yes, it does, some of it. Some signal goes thru the resistor"Sure, some of it does.
let's say you have a 1000 ohm cathode resistor and a 100uf bypass cap.
What portion of a 1000Hz AC signal flows through the resistor?
Let's do the math.
The reactance of the cap at 1000Hz is 1.592 ohms.
So you have a 1000 ohm resistor shunted by a 1.592 ohm resistor.
Let's just pick .1 volts AC at the cathode,
62.814ma flowing through the cap1 / 1.592 = .062814 amps
And .1ma flowing through the resistor.
1 / 1000 = .0001 amps
"Each component has a profound effect on the sound qualities
of the tube's plate and cathode signals. "So you are saying that the cathode resistor that is conducting less than 1/628th of the total AC current at 1000Hz has a profound effect on what the 1000Hz AC signal will sound like? Get real Dennis.
Maybe at lower frequencies where the reactance of the cap is higher but the whole point of a bypass cap is to make it's value is such that the reactance at the lowest frequency of interest is a small fraction of the value of the cathode resistor.*
I'm sure in your design (where the cathode by pass cap is too small) the resistor does carry a lot of low frequency AC (a lot more than it should) and that resistor does make a profound effect on the sound but that's only because your design is flawed.
If you let too much (anything more than a tiny fraction) of the AC flow through the resistor instead of the cap then the bias will change.
That means you will have negative current feedback applied to your output tube and it's plate resistance will increase and the load line will rotate towards the vertical and that will cause an increase of the harmonic distortion as well as a loss of damping factor. (And none of that has anything to do with the sonic properties of the resistor used.)
but you knew all that, right Dennis?
* note, it's really the value of the cathode resistor in parallel with the impedance of the cathode but that discussion is for a different time.P.S. I hope everyone will excuse me for calling 1/628th "none". In my defense, it is very close to none.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 09/03/17 09/03/17
How about comparing that current( the nearly none )to the driver plate current. The percentage is now significant...LOL
All in all, I think *ALL* folks interested in a SE amp should buy one of Dennis-es amps. Wishing you a multitude of sales Dennis!!!
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
I like my flawed design.
It certainly has a way with music, it
almost never fails or suffers any kind of
breakdown, and some people consider it an
example of Industrial Art, and are collecting
them!
There is, of course, a certain hazard in
playing with this kind of equipment when
married: If you are listening to music
because you are enthralled by it, instead
of listening to the "Honey-Do" list--
especially-- then you may indeed see this
design as flawed, when marital distress
occurs!
I do like it, however. I'm proud of it!
-Dennis-
As Tre says: "honest"... and demonstrates a quiet strength absent in the strongly-worded machismo commonly posted here.
Despite my criticism of (your) absolutist posts/ stance and question your technical explanations at times, I respect your passion, uncompromising experimentation, and unwillingness to be boxed in by expert opinion and traditional methods. I'd like to meet you some day and listen to your system.
Take care.
Cheers,
91.
"Confusion of goals and perfection of means seems to characterise our age." Albert Einstein
Got a ticket to Denver?
RMAF 2017, Room 3017.
-Dennis-
Unfortunately not. The flight from Australia's East Coast is brutal.
Cheers,
91
"Confusion of goals and perfection of means seems to characterise our age." Albert Einstein
.
Have Fun and Enjoy the Music
"Still Working the Problem"
WHAT a MESS!
-Dennis-
Dennis, you only see what I posted as being a "MESS" because it's over your head (over your level of understanding).You didn't understand a thing I said.
Read a book. This stuff is not that complicated. You can learn to understand it if you try.
I believe this would help you in the long run.
You could build a circuit the right way (technically speaking) and if you don't like the way it sounds you could then "tweak" it to get the sound you like instead of just doing the whole thing experimentally.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 09/04/17
| FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
||||||||||||||
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]
